Several types of signcutting apparatus suitable for forming signs from adhesive sheet material are known in the graphic arts field, and adhesive sheet materials for use in such machines are available commercially. The machines are used to cut signs which may consist of letters, numbers, symbols, designs etc., including combinations thereof, as required to convey the desired information. The signs may be used primarily for information purposes, such as signage used in factories and other industrial or commercial facilities, or for decorative purposes.
An early form of signcutting apparatus is disclosed in U.S. Pat. No. 3,490,362, Massari, 1970, which involves indirect cutting of an element of adhesive sheet material used to form a sign; the adhesive sheet material is further described in U.S. Pat. No. 3,558,425, Massari, 1971. As taught by this patent, the adhesive sheet material is a three layer construction consisting of a relatively thick and inflexible film coated with pressure sensitive adhesive that is sandwiched between a highly flexible polyester carrier film along its one surface and a relatively inflexible release liner over its adhesive layer. The machine disclosed in U.S. Pat. No. 3,490,362 includes dies which contact, but do not cut, the flexible carrier film, and force is transmitted through the carrier to cut a sign in the intermediate inflexible film material. Thus, the die does not directly contact or penetrate the intermediate layer in this method of sign cutting. Similar techniques and sheet materials are also disclosed in U.S. Pat. No. 4,014,257, Bettenhausen, 1977; U.S. Pat. No. 4,604,153, Malbye, 1986; and U.S. Pat. No. 4,867,056, Anderson et al., 1989. Three layer adhesive sheet material for this type of signcutting machine is sold commercially by Reynolds/Leteron Manufacturing Co. (Inc.).
Microprocessor controlled X-Y plotters have come into widespread use in recent years in the graphic arts industry and they have been employed to provide a second type of signcutting apparatus for producing signs from pressure sensitive adhesive sheet materials. The plotter type of signmaking machines use a knife or razor as a tool for cutting signs in adhesive sheet materials. Movement of the knife and sheet material in a machine of this type are directed by a CPU and programmed instructions so as to cut the sheet material in a sign of the selected configuration. This type of machine is disclosed in a number of U.S. patents, including: U.S. Pat. No. 4,367,588, Herbert, 1983; U.S. Pat. No. 4,467,525, Logan et al., 1984; U.S. Pat. No. 4,512,839, Gerber, 1985; U.S. Pat. No. 4,608,891 Frisby et al., 1986; U.S. Pat. No. 4,732,069, Wood et al., 1988; and U.S. Pat. No. 4,794,542, Proctor 1988. Plotter-type signcutting machines are sold commercially by a number of companies, including Scott Machine Development Corporation, Gerber Scientific and Computer Talk Inc. These machines use a two-layer adhesive sheet material construction consisting of a base tape such as a plastic film coated with adhesive, and a release liner over the adhesive. The base tape is contacted directly by the cutting tool of the machine which penetrates the base tape through to the liner.
A new signmaking apparatus not publicly disclosed at the filing date of this patent is described in a commonly-assigned co-pending patent application identified below which utilizes a dual-acting solenoid to rapidly reciprocate a plunger to form a sign in adhesive sheet material. The new machine is capable of forming signs with various types of adhesive sheet materials.
We have developed new adhesive sheet materials for signmaking apparatus to provide a material having improved physical characteristics, such as with respect to tear resistance and cuttability. Another principal objective of the invention is to provide a novel construction for adhesive sheet material suitable for use with various types of signmaking machines. Another principal objective is to provide an improved adhesive sheet material for sign formation of the type in which a sign tape is sandwiched between a carrier tape and a liner. A more specific objective of the invention is to provide a new adhesive sheet material for signmaking machines that is particularly useful for the new signmaking machine described immediately above. Other objectives of the invention will become apparent from the detailed description which follows.